dt-bindings: auxdisplay: hd44780: Convert to json-schema

DT bindings for the Hitachi HD44780 Character LCD Controller

The Hitachi HD44780 Character LCD Controller is commonly used on character LCDs

that can display one or more lines of text. It exposes an M6800 bus interface,

which can be used in either 4-bit or 8-bit mode.

Required properties:

  - compatible: Must contain "hit,hd44780",

  - data-gpios: Must contain an array of either 4 or 8 GPIO specifiers,

    referring to the GPIO pins connected to the data signal lines DB0-DB7

    (8-bit mode) or DB4-DB7 (4-bit mode) of the LCD Controller's bus interface,

  - enable-gpios: Must contain a GPIO specifier, referring to the GPIO pin

    connected to the "E" (Enable) signal line of the LCD Controller's bus

    interface,

  - rs-gpios: Must contain a GPIO specifier, referring to the GPIO pin

    connected to the "RS" (Register Select) signal line of the LCD Controller's

    bus interface,

  - display-height-chars: Height of the display, in character cells,

  - display-width-chars: Width of the display, in character cells.

Optional properties:

  - rw-gpios: Must contain a GPIO specifier, referring to the GPIO pin

    connected to the "RW" (Read/Write) signal line of the LCD Controller's bus

    interface,

  - backlight-gpios: Must contain a GPIO specifier, referring to the GPIO pin

    used for enabling the LCD's backlight,

  - internal-buffer-width: Internal buffer width (default is 40 for displays

    with 1 or 2 lines, and display-width-chars for displays with more than 2

    lines).

Example:

	auxdisplay {

		compatible = "hit,hd44780";

		data-gpios = <&hc595 0 GPIO_ACTIVE_HIGH>,

			     <&hc595 1 GPIO_ACTIVE_HIGH>,

			     <&hc595 2 GPIO_ACTIVE_HIGH>,

			     <&hc595 3 GPIO_ACTIVE_HIGH>;

		enable-gpios = <&hc595 4 GPIO_ACTIVE_HIGH>;

		rs-gpios = <&hc595 5 GPIO_ACTIVE_HIGH>;

		display-height-chars = <2>;

		display-width-chars = <16>;

	};

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/auxdisplay/hit,hd44780.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Hitachi HD44780 Character LCD Controller

maintainers:

  - Geert Uytterhoeven <geert@linux-m68k.org>

description:

  The Hitachi HD44780 Character LCD Controller is commonly used on character

  LCDs that can display one or more lines of text. It exposes an M6800 bus

  interface, which can be used in either 4-bit or 8-bit mode.

properties:

  compatible:

    const: hit,hd44780

  data-gpios:

    description:

      GPIO pins connected to the data signal lines DB0-DB7 (8-bit mode) or

      DB4-DB7 (4-bit mode) of the LCD Controller's bus interface.

    oneOf:

      - maxItems: 4

      - maxItems: 8

  enable-gpios:

    description:

      GPIO pin connected to the "E" (Enable) signal line of the LCD

      Controller's bus interface.

    maxItems: 1

  rs-gpios:

    description:

      GPIO pin connected to the "RS" (Register Select) signal line of the LCD

      Controller's bus interface.

    maxItems: 1

  rw-gpios:

    description:

      GPIO pin connected to the "RW" (Read/Write) signal line of the LCD

      Controller's bus interface.

    maxItems: 1

  backlight-gpios:

    description: GPIO pin used for enabling the LCD's backlight.

    maxItems: 1

  display-height-chars:

    description: Height of the display, in character cells,

    $ref: /schemas/types.yaml#/definitions/uint32

    minimum: 1

    maximum: 4

  display-width-chars:

    description: Width of the display, in character cells.

    $ref: /schemas/types.yaml#/definitions/uint32

    minimum: 1

    maximum: 64

  internal-buffer-width:

    description:

      Internal buffer width (default is 40 for displays with 1 or 2 lines, and

      display-width-chars for displays with more than 2 lines).

    $ref: /schemas/types.yaml#/definitions/uint32

    minimum: 1

    maximum: 64

required:

  - compatible

  - data-gpios

  - enable-gpios

  - rs-gpios

  - display-height-chars

  - display-width-chars

additionalProperties: false

examples:

  - |

    #include <dt-bindings/gpio/gpio.h>

    auxdisplay {

            compatible = "hit,hd44780";

            data-gpios = <&hc595 0 GPIO_ACTIVE_HIGH>,

                         <&hc595 1 GPIO_ACTIVE_HIGH>,

                         <&hc595 2 GPIO_ACTIVE_HIGH>,

                         <&hc595 3 GPIO_ACTIVE_HIGH>;

            enable-gpios = <&hc595 4 GPIO_ACTIVE_HIGH>;

            rs-gpios = <&hc595 5 GPIO_ACTIVE_HIGH>;

            display-height-chars = <2>;

            display-width-chars = <16>;

    };